The present invention relates to an electric power source unit or, more particularly, to an electric power source unit having improved power output performance with a high-speed pulse-forming circuit or a high-frequency voltage-multipler rectifying circuit built with a ceramic capacitor.
As is known in the art, high-speed pulse-forming circuits are used in the electric power source units suitable for laser excitation, radar-pulse forming, X-ray flash generation, xenon flash excitation and the like including Marx circuits, capacitor bank circuits, L-C inversion circuits and PFN circuits. On the other hand, voltage-multipler rectifying circuits are used in the power source units for television sets, oscilloscopes, X-ray units, electron microscopes, radars, lasers, high voltage lamps, electrostatic copying machines, electrostatic coating machines, electric dust collectors and the like. All of these circuits are composed with polymer film and paper capacitors which may be of the oil-impregnation type, or ceramic capacitors.
Among various types of the capacitors, ceramic capacitors are the most promising ones and rapidly replacing the oil-impregnation type polymer film and paper capacitors widely in conventional uses by virtue of the advantages of the easiness in manufacturing and handling, higher mechanical strengths and larger thermal and chemical stability as well as the possibility of miniaturization.
Most of the ceramic capacitors currently on use are formed of a ceramic of which the ingredient is based on barium titanate. When a barium titanate-based ceramic capacitor is used in the above mentioned high-speed pulse-forming circuits or voltage-multipler rectifying circuits, the proportionality of the power output relative to the applied voltage is satisfactory within a limit of a relatively low applied voltage. In a region of relatively high applied voltages, on the contrary, the proportionality of the power output and the applied voltage is lost and an increase in the applied voltage does not lead to an increase of the power output in proportion. Further increase of the applied voltage over a certain limit necessarily results in leveling off of the power output. In particular, the limiting voltage beyond which the power output levels off is lowered when the ambient temperature is high so that difficulties are encountered in obtaining high power outputs with the circuits.
In recent years, there has been a growing demand to increase the voltage of the power output in the above mentioned types of the electric power source units and it is sometimes desired to apply a voltage to the capacitors as high as the capacitor can withstand. As a consequence, an improvement of the above described drawbacks has become one of the most important problems in the field of the art.
It has been a generally accepted understanding that the above described drawbacks are mostly due to the design of the circuit per se or certain defects in the apparatus design so that efforts have been concentrated in these points but without noticeable success.